JP5620310B2 - Expandable adhesive film, semiconductor dicing film, and semiconductor device manufacturing method using the same - Google Patents

Description

  The present invention relates to an expandable film and a dicing film including the expandable film. The dicing film is useful as an adhesive sheet for fixed support that is cut and divided into element pieces (chips) and attached to the back surface of the wafer in a process of automatically collecting the elements by a pickup method. The present invention also relates to a method for manufacturing a semiconductor device using the dicing film, and a semiconductor device obtained by the manufacturing method.

  In a manufacturing process of a semiconductor device, a silicon wafer on which a predetermined circuit pattern is formed is cut and separated (diced) into element pieces by a rotating round blade (blade). In a process called a dicing process, first, a silicon wafer is attached to a film called a dicing film including a relatively hard base material layer and an adhesive layer having adhesive force through the adhesive layer. Next, a method is generally used in which a silicon wafer is cut into small pieces, the film is stretched both vertically and horizontally, and the distance between elements is increased (see Patent Documents 1 to 3). In addition, in order to prevent device destruction during dicing due to thinning of the wafer in recent years, a semiconductor substrate dicing method (laser ablation dicing) by light absorption ablation of laser light capable of high-definition processing (see Patent Document 4), stealth Dicing, plasma dicing, and the like have been devised, but the process of widening the element spacing using the dicing film is common.

  For this reason, the dicing film is required to be uniformly stretched to some extent without causing necking during stretching regardless of the dicing method. This is because when necking occurs, only the peripheral portion of the film is stretched, the central portion of the film is not sufficiently stretched, and the central element is not easily separated. For this reason, soft vinyl chloride (see Patent Document 5) and a mixture of polyvinyl acetate and an olefin resin (see Patent Document 6), which are difficult to cause necking, are generally used as the expandable base material layer for dicing.

  In recent years, since the wafer is thinned in accordance with high integration of semiconductors, heat generated during dicing reaches the dicing film. For this reason, in a dicing film using soft vinyl chloride, there is a possibility that a plasticizer or the like contained in the vinyl chloride is detached by heating and the semiconductor element is contaminated. In addition, the mixture of polyvinyl acetate and olefin resin has low heat resistance, and the film may be deformed at the time of dicing, so that there is a possibility that the wafer cannot be cracked or uniformly expanded.

  Also, in contrast to the conventional manufacturing method in which baking is performed after dicing, circuit wiring, electrode formation (bonding), resin encapsulation (bonding) formed on the semiconductor wafer after dicing is performed after the dicing film is attached to the wafer ( A manufacturing method called WLP (wafer level package) in which the process is performed until baking) and then dicing is developed and attracting attention (Patent Document 7, etc.). In WLP, the size of the package can be reduced and the semiconductor device can be reduced in size and weight compared to the conventional manufacturing method. However, the dicing film can be used at a temperature required for resin sealing (baking). High heat resistance such as that the dicing film does not deform is required. For this reason, the dicing film which has high heat resistance and expandability which can be used for WLP was calculated | required.

JP-A-2-215528 JP 2008-4836 A JP 2009-267389 A JP 2002-343747 A Japanese Patent Laid-Open No. 2002-235055 JP 2004-303999 A JP 2008-16539 A

  The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a film having both high heat resistance and high uniform expandability that is difficult to neck.

The first of the present invention relates to an expandable substrate film.
[1] An expandable base film containing 4-methyl-1-pentene (co) polymer (A) and a thermoplastic elastomer (B), wherein the content of (B) is (A) and ( The melting point TmB2 derived from (B) is 3 to 50 parts by weight with respect to the total 100 parts by weight of B) and measured by a differential scanning calorimeter (DSC) for the film, or 100 ° C. or less or the melting point TmB2 Expandable base film with virtually no observation.
[2] An expandable base film containing 4-methyl-1-pentene (co) polymer (A) and a thermoplastic elastomer (B), wherein the content of (B) is (A) and ( The melting point TmB1 measured by the differential scanning calorimeter (DSC) of (B) is 100 ° C. or lower or the melting point TmB1 is substantially observed with respect to the total 100 parts by weight of B). Unexpandable base film.
[3] The tensile modulus of elasticity of the 4-methyl-1-pentene (co) polymer (A) measured at 23 ° C. according to ASTM-0638 is 500 to 2000 MPa, as described in [1] or [2]. Expandable base film.
[4] The expansion according to any one of [1] to [3], wherein the thermoplastic elastomer (B) has a tensile elastic modulus at 23 ° C. measured in accordance with JIS K7113-1 of 1 to 50 MPa. Base film.
[5] The expandable base film according to any one of [1] to [4], wherein the thermoplastic elastomer (B) is composed of an olefin elastomer and / or a styrene elastomer.
[6] The expandable base film according to any one of [1] to [5], wherein the density of the thermoplastic elastomer (B) is 850 to 980 kg / m ³ .
[7] 0.3 to 40 weights with respect to 100 parts by weight of the total of 4-methyl-1-pentene (co) polymer (A), thermoplastic elastomer (B) and propylene (co) polymer (C) Expandable base film as described in any one of [1] thru | or [6] containing a part propylene (co) polymer (C).
[8] The film according to claim 1, further comprising a propylene (co) polymer (C), wherein the film has a melting point TmC2 derived from (C) measured by a differential scanning calorimeter (DSC). The expandable substrate film according to [7], wherein is in the range of 110 to 175 ° C.
[9] TEM image of cut surface perpendicular to main surface of substrate (distance in film thickness direction of imaging range is 15 μm and imaging area is 45 μm ² ), 4-methyl-1-pentene (co) polymer The phase dispersion structure of the phase substantially composed of (A) and the phase substantially composed of the thermoplastic elastomer (B) is observed, according to any one of [1] to [8]. Expandable base film.
[10] The expansibility according to any one of [1] to [9], wherein the linear expansion coefficient (1 / K) at 120 ° C. is 1.0 × 10 ^{−4 to} 2.0 × 10 ⁻³ . Base film.

The second of the present invention relates to an expandable adhesive film.
[11] An expandable pressure-sensitive adhesive film comprising a base material layer comprising the expandable base material film according to any one of [1] to [10], and an adhesive layer.
[12] The expandable adhesive film according to [11], wherein the adhesive layer has a tensile elastic modulus at 25 ° C. of 50 MPa or less.
[13] Temperature rising rate of the adhesive layer 2 ° C./min. The expandable pressure-sensitive adhesive film according to [11] or [12], wherein the thermal weight loss rate when the temperature is raised from room temperature to 200 ° C. is less than 2%.
[14] The expandable adhesive film according to any one of [11] to [13], which has an adhesive layer on the outermost surface.
[15] The extension according to any one of [11] to [14], wherein a tensile elastic modulus at 25 ° C. of a layer other than the base material layer is less than a tensile elastic modulus at 25 ° C. Adhesive film.
[16] A semiconductor dicing film comprising the film according to any one of [1] to [15].

3rd of this invention is related with the manufacturing method of an expandable base film.
[17] A 4-methyl-1-pentene (co) polymer (A) and a thermoplastic elastomer having a melting point TmB1 obtained by a differential scanning calorimeter (DSC) of 100 ° C. or lower, or the melting point TmB1 substantially not observed ( B), and a step of forming a melt-kneaded product having a content of (B) of 3 to 50 parts by weight with respect to a total of 100 parts by weight of (A) and (B), [1] Thru | or the manufacturing method of the expandable base film as described in any one of [10].
The fourth of the present invention relates to a method for manufacturing a semiconductor device.
[18] A step of attaching the dicing film according to [16] to a semiconductor wafer via an adhesive layer of the dicing film, a step of dicing the semiconductor wafer to obtain a semiconductor chip, and expanding the dicing film And a step of picking up the semiconductor chip.
[19] A step of attaching the dicing film according to [16] to a surface of the semiconductor wafer having a circuit surface opposed to the circuit surface through an adhesive layer of the film, and sealing the circuit surface of the semiconductor wafer A method for manufacturing a semiconductor device, comprising: a step of dicing the semiconductor wafer to obtain a semiconductor chip; and a step of expanding the dicing film to pick up the semiconductor chip.

It is a cross-sectional TEM photograph parallel to MD direction of the base material layer of the expandable base film which concerns on one Embodiment of this invention. It is a cross-sectional TEM photograph parallel to the TD direction of the base material layer of the expandable base film which concerns on one Embodiment of this invention. It is sectional drawing which shows typically one Embodiment of the expandable base film of this invention. It is a figure explaining a part of manufacturing method of the semiconductor device using the dicing film concerning one embodiment of the present invention. It is a figure explaining a part of manufacturing method of the semiconductor device using the dicing film concerning one embodiment of the present invention. It is a figure explaining a part of manufacturing method of the semiconductor device using the dicing film concerning one embodiment of the present invention. It is a figure explaining a part of manufacturing method of the semiconductor device using the dicing film concerning one embodiment of the present invention. It is a figure explaining a part of manufacturing method of the semiconductor device using the dicing film concerning one embodiment of the present invention. It is the top view and side view explaining the expansion test method of the laminated film in this example. It is a side view explaining the extended test method of the laminated film in this example.

1. Expandable substrate film The expandable substrate film of the present invention comprises 4-methyl-1-pentene (co) polymer (A) and a thermoplastic elastomer (B).

(1) 4-methyl-1-pentene (co) polymer (A)
The 4-methyl-1-pentene (co) polymer (A) is not particularly limited as long as it has a repeating unit derived from 4-methyl-1-pentene. That is, the 4-methyl-1-pentene (co) polymer is a homopolymer of 4-methyl-1-pentene, and 4-methyl-1-pentene other than 4-methyl-1-pentene. It may be a copolymer with a copolymerizable monomer. The “(co) polymer” in the present specification, such as propylene (co) polymer (C) described later, is a homopolymer as in the case of 4-methyl-1-pentene (co) polymer (A). And a copolymer are also included.

  Specifically, the monomer copolymerizable with 4-methyl-1-pentene is an olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene (hereinafter referred to as “olefin having 2 to 20 carbon atoms”). ").

  Examples of olefins having 2 to 20 carbon atoms to be copolymerized with 4-methyl-1-pentene include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1 -Tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-eicosene, and the like are included, and olefins having 10 to 18 carbon atoms are preferable from the viewpoint of imparting appropriate flexibility to the film.

  The olefin having 2 to 20 carbon atoms copolymerized with 4-methyl-1-pentene may be one kind or a combination of two or more kinds. The proportion of the structural unit derived from 4-methyl-1-pentene in the 4-methyl-1-pentene (co) polymer is usually 85 mol% or more, and 90% from the viewpoint of improving the heat resistance described later. More than mol% is preferable. The proportion of structural units derived from olefins having 2 to 20 carbon atoms other than 4-methyl-1-pentene is preferably 15 mol% or less and 10 mol% or less. When the proportion of the structural unit derived from 4-methyl-1-pentene is less than 85 mol%, the elastic modulus of the film is lowered, and the handleability is lowered due to being too soft. Moreover, when it uses for the base material layer of the dicing film mentioned later, the shape of the bonded silicon wafer cannot be hold | maintained and there exists a possibility that problems, such as a wafer breaking, may generate | occur | produce.

  The 4-methyl-1-pentene (co) polymer (A) is preferably a highly crystalline polymer from the viewpoint of making it difficult to break. The crystalline polymer may be either a polymer having an isotactic structure or a polymer having a syndiotactic structure, and is particularly preferably a polymer having an isotactic structure. It is easy to obtain. Furthermore, if 4-methyl-1-pentene (co) polymer can be formed into a film and has a strength that can be used as an expandable base film, the stereoregularity is not particularly limited.

  The tensile elastic modulus at 23 ° C. measured according to ASTM-0638 of the 4-methyl-1-pentene (co) polymer (A) is preferably 500 to 2000 MPa, and more preferably 800 to 1500. If the tensile elastic modulus is larger than the above range, it is too hard and difficult to expand, and if the tensile elastic modulus is too low, it is too soft and handling properties are lowered.

The density measured according to ASTM DM 1505 of the 4-methyl-1-pentene (co) polymer (A) of the present invention is preferably 825 to 840 (kg / m ³ ), 830 to 835 ( More preferably, it is kg / m ³ ). If the density is smaller than the above range, the mechanical strength of the film is lowered, and when used as an expandable substrate, problems such as easy tearing may occur. On the other hand, if the density is larger than the above range, it tends to be too hard to expand.

   The melt flow rate (MFR) of the 4-methyl-1-pentene (co) polymer (A) measured at 260 ° C. and a load of 2.16 kg in accordance with ASTM D1238 is a thermoplastic elastomer (B ) And within the extruder and is not particularly limited as long as it can be co-extruded, but is usually 0.5 to 50 g / 10 min, more preferably 1 to 30 g / 10 min. If MFR is in the above range, it is easy to extrude to a relatively uniform film thickness.

  The 4-methyl-1-pentene (co) polymer (A) may be produced directly by polymerizing olefins, or produced by thermally decomposing a high molecular weight 4-methyl-1-pentene polymer. May be. Further, the 4-methyl-1-pentene (co) polymer may be purified by a method such as solvent fractionation for fractionation based on a difference in solubility in a solvent or molecular distillation for fractionation based on a difference in boiling point.

  When the 4-methyl-1-pentene (co) polymer is directly produced by a polymerization reaction, for example, the amount of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the kind of polymerization catalyst, the polymerization The melting point, stereoregularity, molecular weight and the like are controlled by adjusting the temperature, the amount of hydrogenation during polymerization, and the like. The method for producing the 4-methyl-1-pentene (co) polymer by a polymerization reaction may be a known method. For example, it can be produced by a method using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst, preferably using a metallocene catalyst. On the other hand, when the 4-methyl-1-pentene (co) polymer is produced by pyrolyzing a higher molecular weight 4-methyl-1-pentene polymer, the temperature and time of the pyrolysis are controlled. Thus, the desired molecular weight is controlled.

  The 4-methyl-1-pentene (co) polymer (A) may be a commercially available polymer such as TPX manufactured by Mitsui Chemicals, Inc. in addition to the one produced as described above.

(2) Thermoplastic elastomer (B)
The thermoplastic elastomer (B) contained in the expandable substrate film of the present invention is mixed with the expandable substrate film itself of the present invention, that is, at least the aforementioned 4-methyl-1-pentene (co) polymer (A). The melting point TmB2 measured by a differential scanning calorimeter (DSC) is 100 ° C. or less or substantially no melting point TmB2 is observed with respect to the one in the state of being in the state of scanning calorimeter ( The melting point TmB1 measured by DSC) is 100 ° C. or lower, or substantially no melting point TmB2 is observed.

  By adjusting the melting point TmB1 or the melting point TmB2 to be lower than the temperature at the time of heat sealing described later, or by using a thermoplastic elastomer that does not have a melting point in the first place, that is, a low crystalline and thermoplastic elastomer, The thermoplastic elastomer (B) and 4-methyl-1-pentene (co) polymer (A) are finely dispersed to form an alloy structure (also referred to as a phase dispersion structure), and expandability without impairing heat resistance. Can be improved.

  The melting point TmB1 of the thermoplastic elastomer (B) alone and the melting point TmB2 of the thermoplastic elastomer (B) in the film are usually almost the same, but the aforementioned 4-methyl-1-pentene (co) polymer (A) When the crystallinity of other components described later is high, the melting point of the thermoplastic elastomer (B) itself may change due to the influence of these crystal components. Further, even when the thermoplastic elastomer (B) having no melting point alone is used, the melting point TmB2 in the film may be observed, but the difference between TmB1 and TmB2 is usually within 20 ° C. Further, by using the thermoplastic elastomer (B) having a melting point of 100 ° C. or lower or a melting point substantially not observed, a film having a melting point TmB of 100 ° C. or lower or substantially no melting point TmB 2 can be obtained.

  The thermoplastic elastomer (B) may have rubber elasticity at the handling temperature of the expandable film, and preferably has a glass transition point of 25 ° C. or lower. When the glass transition point exceeds 25 ° C., there is a concern that physical properties such as extensibility of the film after molding are likely to change depending on storage conditions.

  The thermoplastic elastomer (B) is not particularly limited as long as it is a thermoplastic elastomer having the above-mentioned melting point, and specific examples include olefin-based elastomers and styrene-based elastomers.

  Specific examples of the olefin elastomer include a propylene / α-olefin copolymer, that is, a copolymer of propylene and an α-olefin other than propylene. The α-olefin in the propylene / α-olefin copolymer is preferably an α-olefin having 2 to 20 carbon atoms. Examples of the α-olefin having 2 to 20 carbon atoms include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene and 1-decene, preferably Ethylene, 1-butene. The α-olefin contained in the propylene / α-olefin copolymer may be one type or a combination of two or more types. The propylene / α-olefin copolymer is more preferably a propylene / 1-butene / ethylene copolymer. The content of the structural unit derived from propylene of the propylene / α-olefin copolymer is preferably 50 mol% or more, more preferably 60 mol% or more, from the viewpoint of obtaining good moldability.

  The styrene elastomer is composed of polystyrene as a hard segment and polybutadiene, polyisoprene, a copolymer of polybutadiene and polyisoprene, or a hydrogenated product thereof as soft segments. Hydrogenation may be performed only on a part of polybutadiene or polyisoprene, or all may be hydrogenated. Such styrenic elastomers can be imparted with good adhesion by being modified with functional groups such as carboxylic acid groups, acid anhydride groups, amino groups, epoxy groups and hydroxyl groups. Commercially available modified styrene elastomers include “Tuftec” (manufactured by Asahi Kasei Chemicals, registered trademark), “Clayton” (manufactured by Kraton Polymer Japan, registered trademark), “Dynalon” (manufactured by JSR, registered trademark), “ Septon "(manufactured by Kuraray Co., Ltd., registered trademark)," SIBSTER "(manufactured by Kaneka Corporation, registered trademark), and the like.

  Olefin-based elastomers and styrene-based elastomers can be obtained by copolymerizing monomers (monomers) constituting the elastomer in the presence of a conventionally known production method, for example, a Ziegler-Natta catalyst or a metallocene-based catalyst. Specifically, the propylene / α-olefin copolymer can be obtained by copolymerizing propylene and an α-olefin other than propylene.

  1-50 MPa is preferable and, as for the tensile elasticity modulus in 23 degreeC measured based on JISK7113-2 of a thermoplastic elastomer (B), 3-45 MPa is more preferable. When the tensile elastic modulus is smaller than the above range, the handling property of the film is lowered. On the other hand, if the tensile elastic modulus is larger than the above range, the flexibility of the film of the present invention is lowered, and the base film may be broken during expansion.

Further preferably the density is measured in accordance with ASTM DM1505 of the thermoplastic elastomer (B) is a 850~980kg / m ^3, more preferably 860~970kg / m ^3.

  The melt flow rate (MFR) measured at 260 ° C. under a load of 2.16 kg in accordance with ASTM D1238 of the thermoplastic elastomer (B) is an extrusion with the 4-methyl-1-pentene (co) polymer (A). It is not particularly limited as long as it is easy to mix in the machine and can be co-extruded. As described later, in order to improve the handling property of the thermoplastic elastomer (B), a propylene (co) polymer (C) and the thermoplastic elastomer (B) are mixed to prepare a mixture, and then 4-methyl-1- When the pentene (co) polymer (A) and the mixture are mixed in an extruder, the melt flow rate (MFR) of the mixture of the thermoplastic elastomer (B) and the propylene (co) polymer (C) is preferably 1 It is -50g / 10min, More preferably, it is 3-40g / 10min. If MFR is in the above range, it is easy to extrude to a relatively uniform film thickness.

  The content of the thermoplastic elastomer (B) contained in the expandable base film of the present invention is 100 parts by weight in total of the 4-methyl-1-pentene (co) polymer (A) and the thermoplastic elastomer (B). It is preferable that it is 3-50 weight part with respect to it, and it is more preferable that it is 5-40 weight part. By including the 4-methyl-1-pentene (co) polymer (A) and the thermoplastic elastomer (B) at the above ratio, the component A and the component B are appropriately phase-dispersed as described later, for example, When the expandable substrate film of the present invention is used as the substrate layer of the dicing film, high and uniform expandability can be imparted without greatly impairing the heat resistance.

In the expandable substrate film of the present invention, the 4-methyl-1-pentene (co) polymer (A) having a relatively high crystallinity and the thermoplastic elastomer composition (B) are phase-separated and dispersed. It is preferable to have a structure (phase dispersion structure). Specifically, a sea-island structure or a laminated structure is observed in a TEM image of the cut surface perpendicular to the main surface of the film of the present invention (distance in the film thickness direction of the imaging range is 15 μm and imaging area is 45 μm ² ), The sea part is substantially composed of the 4-methyl-1-pentene copolymer (A), and the island part is substantially composed of the propylene-based elastomer composition (B). Is preferred. Such a phase-separated structure is not formed by the high crystalline olefin resin and the low crystalline olefin resin exemplified in Japanese Patent No. 3340979, so that the 4-methyl-1-pentene ( It is considered to be manifested by the combination of the (co) polymer (A) and the propylene-based elastomer composition (B).

  FIG. 1A is an example of a TEM image of a cross section parallel to the MD direction of the expandable substrate film of the present invention, and FIG. 1B is a TEM image of a cross section parallel to the TD direction of the expandable substrate film of the present invention. It is an example. As shown in FIGS. 1A and 1B, in the film cross-sectional TEM images in the MD direction and the TD direction, a bright portion extending in a direction parallel to the film surface, that is, a portion having a lower electron density than the dark portion is seen. Such a phase dispersion structure can be observed as a “light / dark structure” by a transmission electron microscope (TEM) image obtained by observing a cross section of the expandable substrate film of the present invention in a thin slice. In the TEM image of FIG. 1A, for example, “bright part” is 4-methyl-1-pentene (co) polymer (A) having a relatively low electron density; “dark part” is heat having a relatively high electron density. 4-Methyl-1-pentene (co) which is relatively compatible with thermoplastic elastomer (B), such as plastic elastomer (B) or thermoplastic elastomer (B), propylene (co) polymer (C) described later. It is considered to be a mixture of compounds having low phase solubility with the polymer (A).

  The mechanism that the phase dispersion structure exerts on the effect of the present invention is not necessarily clear, but is presumed as follows. That is, when stress is applied to the expandable film having the phase separation structure as described above, the 4-methyl-1-pentene (co) polymer (A) is elastically deformed and is not yet necked. Via B), the stress applied to the 4-methyl-1-pentene (co) polymer (A) is made uniform in the cross-sectional direction of the film. For this reason, the higher-order structure of the 4-methyl-1-pentene (co) polymer (A) is isotropically deformed as a whole of the expandable film, and the range of elastic deformation without necking is widened, that is, high. It is thought that extensibility appears.

(3) Propylene (co) polymer (C)
The expandable substrate film of the present invention may further contain a propylene (co) polymer (C). By including such a propylene (co) polymer (C), effects such as an effect of suppressing blocking during kneading of raw materials or film forming, and an effect of improving film formability can be expected.

   The propylene (co) polymer (C) is substantially a homopolymer of propylene, but may contain a small amount of α-olefin other than propylene, so-called homopolypropylene (hPP), random polypropylene (rPP) and Any of block polypropylene (bPP) may be used. The content of α-olefin other than propylene in polypropylene is preferably 20 mol% or less, more preferably 10 mol% or less.

  When the propylene (co) polymer (C) is contained in the film of the present invention, the film itself of the present invention itself, that is, at least the aforementioned 4-methyl-1-pentene (co) polymer (A) and a thermoplastic elastomer ( The melting point TmC2 measured by a differential scanning calorimeter (DSC) is preferably 110 ° C. to 175 ° C., more preferably 120 ° C. to 170 ° C. with respect to the mixture of B) and component C.

  The melting point TmC1 of the propylene (co) polymer (C) consisting essentially of the propylene (co) polymer (C) and the melting point TmC2 of the propylene (co) polymer (C) in the film are usually And kneading the thermoplastic elastomer (B), which is substantially the same but has a low melting point or substantially no melting point, and the 4-methyl-1-pentene (co) polymer (A) having a high melting point, When a dispersion structure is formed, TmC2 may be higher or lower than TmC1, but the difference between TmC1 and TmC2 is usually within 20 ° C.

  The content of the propylene (co) polymer (C) is preferably 0.3 to 40 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). More preferably, it is 0.5 to 25 parts by weight. Moreover, when there is much quantity of a component (C), it is preferable to increase content of a component (B). If the content of the propylene (co) polymer (C) is less than 5 parts by weight, the thermoplastic elastomer (B) may be easily blocked. On the other hand, when it exceeds 40 weight part, when the film of this invention is used as an expandable base film, expandability may fall.

(4) Other components The expandable substrate film of the present invention is preferably substantially composed of the above-mentioned component A and component B and / or component (C) in order to form the aforementioned phase separation structure, Other resins and additives may be included as long as the object of the present invention is not impaired. Examples of the additive include a heat stabilizer, a weather stabilizer, a rust inhibitor, a copper damage stabilizer, and an antistatic agent. It is preferable that content of an additive shall be 0.0001-10 mass parts with respect to 100 mass parts of the whole resin composition which comprises the film of this invention.

  The expandable film of the present invention has high heat resistance, good handling properties, and excellent expandability. For this reason, the expandable film of the present invention can be used as a base material layer of dicing films used for manufacturing various types of applications requiring expandability, for example, protective members such as optical elements and semiconductor devices, It is preferably used for a semiconductor device manufacturing method including a step of dicing a semiconductor wafer, which requires heat resistance of the dicing film, and a semiconductor device manufacturing by a WLP process.

2. About the expandable adhesive film The expandable adhesive film of the present invention has a base material layer containing the above expandable base film and an adhesive layer, and may further have a low friction layer or the like as necessary. .

About the pressure-sensitive adhesive layer The pressure-sensitive adhesive layer may be composed of a known pressure-sensitive adhesive, and is not particularly limited. For example, in addition to rubber-based, acrylic-based, and silicone-based pressure-sensitive adhesives, thermoplastic pressure-sensitive adhesives such as styrene-based elastomers and olefin-based elastomers. You may be comprised with material. Further, the pressure-sensitive adhesive layer may be composed of a radiation curable pressure-sensitive adhesive that reduces the pressure-sensitive adhesive force by radiation, a heat-curable pressure-sensitive adhesive that decreases the pressure-sensitive adhesive strength by heating, or the like. A preferable example of the radiation curable pressure sensitive adhesive includes an ultraviolet curable pressure sensitive adhesive. Moreover, when using the expandable adhesive film of this invention as a dicing film for semiconductors, it can also have the adhesive layer of Unexamined-Japanese-Patent No. 2005-277297.

  The acrylic pressure-sensitive adhesive may be a homopolymer of an acrylate compound or a copolymer of an acrylate compound and a comonomer. Examples of the acrylate compound include ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate. Examples of comonomer constituting the acrylic copolymer include vinyl acetate, acrylonitrile, acrylamide, styrene, methyl methacrylate, methyl acrylate, methacrylic acid, acrylic acid, itaconic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, dimethylamino Examples include ethyl methacrylate, acrylic amide, methylol acrylic amide, glycidyl methacrylate and maleic anhydride.

  Examples of rubber-based adhesives include natural rubber, synthetic isoprene rubber, styrene butadiene rubber, styrene / butadiene block copolymer, styrene / isoprene block copolymer, butyl rubber, polyisobutylene, polybutadiene, polyvinyl ether, silicone rubber, and Chloroprene rubber and the like are included.

  A tackifier resin may be further added to the rubber-based pressure-sensitive adhesive in order to increase the adhesive strength. Examples of tackifying resins include rosin resins and terpene resins, and are preferably terpene resins from the viewpoint of good compatibility with rubber adhesives. Examples of rosin resins include rosin, polymerized rosin, hydrogenated rosin, rosin ester, etc .; examples of terpene resins include terpene resins, terpene phenol resins, aromatic modified terpene resins and rosin phenol resins, etc. Is included. It is preferable that content of tackifying resin is 5-100 weight part with respect to 100 weight part of rubber-type adhesives.

  The ultraviolet curable pressure-sensitive adhesive and the heat-curable pressure-sensitive adhesive are a pressure-sensitive adhesive such as the acrylic pressure-sensitive adhesive, a curable compound (a component having a carbon-carbon double bond), a photopolymerization initiator or a thermal polymerization initiator, ,including.

  The curable compound may be any monomer, oligomer or polymer having a carbon-carbon double bond in the molecule and curable by radical polymerization. Examples of such curable compounds include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neo Esters of (meth) acrylic acid and polyhydric alcohols such as pentyl glycol di (meth) acrylate and dipentaerythritol hexa (meth) acrylate; ester acrylate oligomers; 2-propenyl di-3-butenyl cyanurate, 2-hydroxyethyl Examples include isocyanurates or isocyanurate compounds such as bis (2-acryloxyethyl) isocyanurate and tris (2-methacryloxyethyl) isocyanurate. In addition, when an adhesive is an ultraviolet curable polymer which has a carbon-carbon double bond in the side chain of a polymer, it is not necessary to add a sclerosing | hardenable compound.

  The content of the curable compound is preferably 5 to 900 parts by weight with respect to 100 parts by weight of the pressure-sensitive adhesive, and more preferably 20 to 200 parts by weight. If the content of the curable compound is too small, there are too few parts to be cured, and the adjustment of the adhesive strength becomes insufficient, and if the content of the curable compound is too large, the sensitivity to heat and light is too high and the storage stability is high. Decreases.

  The photopolymerization initiator may be any compound that can be cleaved by irradiation with ultraviolet rays to generate radicals. For example, benzoin alkyl ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzyl, benzoin, benzophenone, α -Aromatic ketones such as hydroxycyclohexyl phenyl ketone; aromatic ketals such as benzyldimethyl ketal; polyvinyl benzophenone; thioxanthones such as chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, and diethylthioxanthone.

  The thermal polymerization initiator is an organic peroxide derivative or an azo polymerization initiator, and is preferably an organic peroxide derivative from the point that nitrogen is not generated during heating. Examples of the thermal polymerization initiator include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxyester, peroxydicarbonate, and the like.

  You may add a crosslinking agent to an adhesive. As cross-linking agents, epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether; tetramethylolmethane-tri-β-aziridinylpropionate, trimethylol Propane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N′-hexamethylene-1,6-bis (1-aziridine Aziridine compounds such as carboxyamide); isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, and polyisocyanate.

  Adhesive strength measured in accordance with JIS Z0237 when peeling from the surface of the SUS-304-BA plate after the pressure-sensitive adhesive layer is adhered to the surface of the SUS-304-BA plate and left standing for 60 minutes. It is preferable that it is 0.1-10N / 25mm. If the adhesive strength is in the above range, it is possible to suppress the adhesive residue when the chip is peeled off while ensuring good adhesion to the wafer. The adhesive strength of the pressure-sensitive adhesive layer can be adjusted by, for example, the amount of crosslinking agent added. Specifically, it can be adjusted by the method described in JP-A No. 2004-155591.

Regarding the low-friction layer When the expandable adhesive film of the present invention is used as a dicing film for semiconductors, it further has a low-friction layer on the surface opposite to the surface on which the adhesive layer of the base material layer is formed. May be.

  That is, when the dicing film is used as a semiconductor dicing film as will be described later, as a method of expanding the dicing film, the peripheral portion of the dicing film is fixed with a ring frame, and the dicing film is expanded from below the center of the dicing film. There is a method of pushing up the stage of the machine (see FIG. 4 described later). At this time, if the friction of the surface of the dicing film on the side in contact with the stage is large, the film is difficult to slide on the stage, and the film portion in contact with the stage cannot be expanded. For this reason, reducing the friction of the surface of the dicing film on the side in contact with the stage; that is, by arranging a low friction layer, the expansion machine stage can be made slippery and the entire surface of the dicing film can be expanded uniformly. it can.

  Such a low friction layer is made of a resin such as polyethylene or ethylene ionomer resin. Further, a lubricant may be applied or contained on the surface of the low friction layer in order to further improve the slipperiness as necessary. Examples of such lubricants include lubricants such as erucic acid amide, oleic acid amide, and silicone oil, and master batches thereof (lubricant master batch).

  The layer structure in particular of the dicing film of this invention is not restrict | limited, What is necessary is just a film which consists of at least 2 layers of a base material layer and an adhesive layer. Three or more laminated films having other layers such as a low friction layer in addition to the pressure-sensitive adhesive layer may be used. When the dicing film of the present invention is the laminated film, it is preferable that the pressure-sensitive adhesive layer is disposed on one surface of the base material layer, and the low friction layer is disposed on the other surface of the base material layer. The base material layer and the pressure-sensitive adhesive layer may each be a multilayer.

  FIG. 2 is a cross-sectional view schematically showing one embodiment of the dicing film of the present invention. As shown in FIG. 2, the base material layer 12 having expandability, the pressure-sensitive adhesive layer 14 disposed on one surface thereof and bonded to the wafer, and the side of the base material layer opposite to the pressure-sensitive adhesive layer 12 And a low friction layer 16 disposed on the surface. Since the dicing film 10 having such a configuration has the base material layer 12, it has high expandability.

  The total thickness of the dicing film of the present invention is preferably 50 to 200 μm, and more preferably 70 to 150 μm.

  The dicing film of the present invention preferably has a tensile elastic modulus (initial elastic modulus) at 23 ° C. of 70 MPa or more. This is because when the pressure is 70 MPa or less, the dicing film becomes wrinkles when the dicing film is attached to the wafer, and the handling property is prevented from being lowered.

  In order to protect the pressure-sensitive adhesive layer surface, a separator may be further provided on the surface of the pressure-sensitive adhesive layer of the dicing film of the present invention as necessary. The material of the separator may be paper, a synthetic resin film such as polyethylene, polypropylene, and polyethylene terephthalate. The thickness of a separator is about 10-200 micrometers normally, Preferably it is about 25-100 micrometers.

  Since the expandable film of the present invention does not contain polyvinyl chloride (PVC) or the like, it does not generate chlorine ions and can reduce the environmental burden. Moreover, since the expandable film of the present invention does not contain a plasticizer, contamination of the wafer can be reduced. Furthermore, the expandable film of the present invention has sufficient expandability and is less likely to cause necking.

3. Method for producing expandable substrate film The expandable substrate film of the present invention can be produced by an arbitrary method, but is a 4-methyl-1-pentene copolymer (A) and a differential scanning calorimeter (DSC). The resulting melting point TmB1 comprises 100 ° C. or less or a thermoplastic elastomer (B) in which the melting point TmB1 is not substantially measured, and the content of (B) is 100 parts by weight in total of (A) and (B). On the other hand, it is preferable to manufacture by the manufacturing method including the process of shape | molding 3-50 weight part melt-kneaded material.

  A specific method for forming a film is, for example, 1) Melting and kneading pellets of 4-methyl-1-pentene (co) polymer (A) and pellets of thermoplastic elastomer (B) with an extruder, and extrusion. Method of forming expandable substrate film by molding (dry blend method); 2) 4-methyl-1-pentene (co) polymer (A) and thermoplastic elastomer (B) with a twin screw extruder or the like Melt-kneaded and melt-blended melt blend resin is again melt-kneaded in an extruder and extruded to produce an expandable substrate film (melt blend method); 3) 4-methyl-1-pentene (co-polymer) There is a method (press film method) of pressing a melt blend resin obtained by melting and kneading the polymer (A) and the thermoplastic elastomer (B) with an extruder or the like to a predetermined thickness with a press.

  When the expandable substrate film is produced by the extrusion molding of 1) and 2), the extrusion temperature is such that the 4-methyl-1-pentene (co) polymer (A) and the thermoplastic elastomer (B) are uniform. The temperature may be any temperature as long as it can be kneaded and formed to have a uniform thickness, for example, about 230 to 290 ° C. Extrusion molding can be performed by a known extruder having, for example, a T die or an inflation die.

  When producing an expandable substrate film by press molding of the above 3), the pressing conditions are uniform by melting 4-methyl-1-pentene (co) polymer (A) and thermoplastic elastomer (B). What is necessary is just to set to the conditions which can be shape | molded to the sheet | seat of thickness. The press temperature can be set to, for example, about 230 to 290 ° C. Press molding can be performed with a known press.

  When the above-mentioned propylene (co) polymer (C) is added, the propylene (co) polymer is separated from the 4-methyl-1-pentene (co) polymer (A) and the thermoplastic elastomer (B). (C) may be added, but after preparing a mixture (hereinafter also referred to as composition D) in which the thermoplastic elastomer (B) and the propylene (co) polymer (C) are kneaded in advance, the composition In some cases, it is easier to produce the expandable substrate film by kneading (D) and the 4-methyl-1-pentene (co) polymer (A). This is because the thermoplastic elastomer (B), which is viscous even near room temperature, is difficult to handle by itself, and when molded into a pellet and stored, the pellets may stick together, so that propylene (co) heavy having a high melting point. This is because mixing the component (C) with the component B to prepare a mixture can reduce the viscosity of the mixture and improve handling properties. Moreover, after preparing the composition (D) which is a component which becomes an island part of the said phase dispersion structure previously, it mixes with the 4-methyl-1-pentene (co) polymer (A) used as the sea part of the said phase dispersion structure. Thus, it is considered that a phase dispersion structure can be easily formed by manufacturing a film.

4). Manufacturing Method of Semiconductor Device A manufacturing method of a semiconductor device using the dicing film of the present invention is 1) a step of attaching the dicing film of the present invention to the back surface of the semiconductor wafer via an adhesive layer, and 2) dicing the semiconductor wafer 3) expanding the dicing film, and picking up the diced semiconductor wafer (semiconductor chip); 4) mounting the semiconductor chip by bonding it to a die pad (not shown) of the semiconductor device. It is manufactured through a process. The dicing film described above can be used as the dicing film of the present invention.

  3A to 3E are diagrams illustrating an example of a method for manufacturing a semiconductor device. As shown in FIG. 3A, a wafer 22 is prepared. Next, as shown in FIG. 3B, the wafer 22 is attached to the dicing film 30 including the expandable substrate film of the present invention (step 1). The dicing film 30 has a diameter larger than that of the wafer 22, and has a size that allows the periphery of the dicing film 30 to be fixed by the ring frame 26. Then, the peripheral edge portion of the dicing film 30 is fixed by the ring frame 26.

  Next, as shown in FIG. 3C, the wafer 22 is diced (cut) to obtain semiconductor chips 22A (step 2). The cutting depth may be set to such an extent that it reaches the interface between the base material layer 32 and the pressure-sensitive adhesive layer 34 of the dicing film 30. The cutting means is not particularly limited, and may be a dicing saw or a laser.

  Next, as shown in FIG. 3D, the dicing film 30 is expanded (step 3). The means for expanding (expanding) the dicing film 30 is a method of expanding the dicing film 30 in contact with the stage by raising the stage of the expansion machine below the dicing film 30, or pulling (expanding) the film in a direction parallel to the film surface. ) Method etc. are included.

  Thereby, as shown in FIG. 3E, the interval between the semiconductor chips 22A obtained by dicing can be increased. Further, by expanding (expanding) the dicing film 30, shear stress is generated between the pressure-sensitive adhesive layer 34 of the dicing film 30 and the wafer 22, and the adhesive force between the wafer 22 and the pressure-sensitive adhesive layer 34 is reduced. The semiconductor chip 22A can be easily picked up. As described above, when the semiconductor chip 22 </ b> A is picked up, the semiconductor chip 22 </ b> A can be peeled from the adhesive layer 34 of the dicing film 30.

  Further, in the case of WLP (wafer level package), before the step 2) in FIG. 3C, an electrode is formed by a commonly used method on the circuit surface facing the surface on which the dicing film is bonded, Even resin sealing (baking) is performed.

  The resin used for baking is usually a baking resin to be used, and is not particularly limited. However, a thermosetting epoxy resin, a thermoplastic polyimide, or the like is used. The baking temperature depends on the curing temperature and softening temperature of the used baking resin, but is usually 100 to 120 ° C.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this.

(1) 4-methyl-1-pentene copolymer (A)
As 4-methyl-1-pentene copolymer (A) contained in the expandable substrate film, 4-methyl-1-pentene copolymer (A1) shown in Table 1 (trade names: TPX DX310, Mitsui Chemicals ( Co., Ltd.), 4-methyl-1-pentene copolymer (A2) (trade name TPX MX004, manufactured by Mitsui Chemicals), 4-methyl-1-pentene copolymer (A3) (trade name TPX MX002) And Mitsui Chemicals, Inc.). Furthermore, 1) tensile elastic modulus (room temperature) 2) MFR of 4-methyl-1-pentene copolymers (A1) to (A3) were measured as follows. The results are shown in Table 1.
1) Tensile modulus (room temperature)
Based on ASTM-0638, the elastic modulus was measured about the injection-molded body.
2) Measurement of MFR Measurement was performed under conditions of a temperature of 240 ° C. or 260 ° C. and a load of 2.16 kg in accordance with ASTM D1238.
3) Measurement of melting point It was determined from the peak temperature according to JIS K7121.

(2) Thermoplastic elastomer (B)
(Synthesis Example 1)
After charging 833 ml of dry hexane, 100 g of 1-butene, and 1.0 mmol of triisobutylaluminum in a 2000 ml polymerization apparatus sufficiently purged with nitrogen, the temperature in the polymerization apparatus was raised to 40 ° C. The pressure in the system was increased to 0.76 MPa with propylene. Next, the pressure in the polymerization apparatus was adjusted to 0.8 MPa with ethylene. Next, 0.001 mmol of dimethylmethylene (3-tert-butyl-5-methylcyclopentadienyl) fluorenylzirconium dichloride was brought into contact with 0.3 mmol of methylaluminoxane (made by Tosoh Finechem) in terms of aluminum. The toluene solution was added to the polymerization apparatus, polymerized for 20 minutes while maintaining the internal pressure at 0.8 MPa with ethylene at an internal temperature of 40 ° C., and then 20 ml of methanol was added to stop the polymerization reaction. After depressurization, the polymer was precipitated from the polymerization solution in 2 L of methanol and dried under vacuum at 130 ° C. for 12 hours to obtain 36.4 g of a thermoplastic elastomer (B1).

(Synthesis Examples 2-3)
Thermoplastic elastomers (B2) to (B3) were obtained in the same manner as in Synthesis Example 1 except that the copolymerization ratio of propylene, ethylene and 1-butene was changed as shown in Table 2.
The compositions of the thermoplastic elastomers (B1) to (B3) obtained in Synthesis Examples 1 to 3 are summarized in the table. The results are shown in Table 2. In addition, mol% in a table | surface is mol% when the sum total of the propylene in a thermoplastic elastomer (B), ethylene, and 1-butene is 100 mol%.

(3) Synthesis of Composition (D) Composition (D), which is a mixture of thermoplastic elastomer (B) and propylene (co) polymer (C), was synthesized as follows.
(Synthesis Example 4)
90 parts by weight of the thermoplastic elastomer (B1) obtained in Synthesis Example 1 and 10 parts by weight of homopolypropylene (C1) as a propylene (co) polymer (C) (prime polymer F107BV, melting point = 160 ° C., 260 MFR at 14 ° C. = 14 g / 10 min) was kneaded at 200 ° C. with a twin screw extruder to obtain a composition (D1).
(Synthesis Example 5)
95 parts by weight of the thermoplastic elastomer (B2) obtained in Synthesis Example 2 and 5 parts by weight of homopolypropylene (C1) as a propylene (co) polymer (C) (F107BV made of prime polymer, melting point = 160 ° C., 260 A composition (D2) was obtained in the same manner as in Synthesis Example 4 except that the MFR at 14 ° C. was kneaded.
(Synthesis Example 6)
85 parts by weight of the thermoplastic elastomer (B3) obtained in Synthesis Example 3 and 15 parts by weight of homopolypropylene (C1) as a propylene (co) polymer (C) (prime polymer F107BV, melting point = 160 ° C., 260 A composition (D3) was obtained in the same manner as in Synthesis Example 4, except that MFR at 14 ° C. was 14 k / 10).
MFR of the obtained compositions (D1) to (D3) was measured in the same manner as described above. 4) Tensile modulus (room temperature) and 5) Density was measured as below, and melting point was measured in the same manner as 3) melting point. The results are shown in Table 3.
4) Tensile modulus (room temperature)
In accordance with JIS K7113-2, the test temperature was room temperature (23 ° C.), the test speed was 200 mm / min, and the elastic modulus in the MD direction of the film was measured.
5) Density The density was measured according to ASTM D1505.

(Synthesis Example 7)
80 parts by weight of 4-methyl-1-pentene copolymer (A1) and 20 parts by weight of the composition (D1) obtained in Synthesis Example 4 were kneaded at 260 ° C. in a twin screw extruder, E1) was obtained.
(Synthesis Examples 8 to 19)
Synthetic Example 7 and Synthetic Example 7 except that 4-methyl-1-pentene copolymer (A), composition (D), and propylene (co) polymer (C) were used in the proportions shown in Table 4. Similarly, mixtures (E2) to (E13) were obtained.
MFR of the obtained mixtures (E1) to (E9) was measured in the same manner as described above. The results are shown in Table 4.

  Further, the melting points of the obtained mixtures (E1) to (E9) were measured in the same manner as 5) above, and TmA2, TmB2, and TmC2 were determined. As a result, the TmA2 of the mixture E6 is 224 ° C, the TmB2 is 47 ° C, the TmC2 is 159 ° C, the TmA2 of the mixture E8 is 224 ° C, the TmB2 is 45 ° C, the TmC2 is 158 ° C, and the TmA2 of the mixture E10 is 224 ° C , TmB2 was found to be 43 ° C, and TmC2 was found to be 157 ° C. As shown in Tables 1 and 3, TmA1 is 223 to 224 ° C., TmB1 is 49 ° C., and TmC1 is 159 ° C. As described above, TmA1 and TmA2, TmB1 and TmB2, and TmC1 and TmC2 are respectively It can be seen that there is no significant difference in temperature.

Example 1
Film Formation A mixture (E1) was prepared as a raw material for the base layer (expandable base film). Composition D3 was prepared as a raw material for the adhesive layer.

Method for forming co-pressing adhesive layer Next, the raw material of the base material layer was put into an extruder equipped with a full flight type screw for extruding the base material layer. Further, the raw material for the adhesive layer was put into an extruder equipped with a full flight type screw. The raw material of the base material layer and the raw material of the adhesive layer were melt-kneaded in respective separate extruders. Next, the extrusion temperature of the base material layer and the adhesive layer is set to 230 ° C., and two layers of molten resin of the base material layer and the adhesive layer are laminated in a multilayer die and co-extruded, as shown in FIG. In addition, an expandable adhesive film having a two-layer structure in which a base material layer and an adhesive layer were sequentially laminated was obtained. A separator (trade name SP-PET, manufactured by Tosero Co., Ltd.) was further laminated on the adhesive layer of the obtained laminated film, and then slit and wound up to a predetermined width.

(Examples 2-13, Comparative Examples 1-2)
An expandable adhesive film was obtained in the same manner as in Example 1 except that the mixture E1 was changed to a material as shown in Table 5 as a material for the expandable substrate film. In Comparative Example 1, 4-methyl-1-pentene copolymer (A2) is used as a raw material for the base material layer instead of the mixture (E). In Comparative Example 2, 4-methyl-1-pentene copolymer ( A3) was used.

  The films obtained in Examples and Comparative Examples were evaluated for 6) expandability and 7) linear expansion coefficient as follows. These results are shown in Tables 6 and 7. Further, 8) TEM observation was performed as follows for some examples of films. These results are shown in FIGS. 1A and 1B. In Tables 4 to 7, F107BV is homopolypropylene h-PP (trade name F107BV, manufactured by Prime Polymer Co., Ltd.).

  In addition, the stress-strain curve (also referred to as SS curve) of the expandable adhesive film was measured in the same manner as in 1) tensile elastic modulus (room temperature), and from the initial slope of the curve where stress was applied. Tensile modulus was calculated. The film obtained in Example 3 had a tensile modulus of 75 MPa, the film obtained in Example 4 was 93 MPa, and the film obtained in Example 11 was 91 MPa.

6) Linear expansion coefficient The heat resistance of the film was measured by thermomechanical analysis (TMA). The measurement was performed by using a TMA / SS120 manufactured by Seiko Instruments Inc. to measure expansion and compression. The film width was 4 mm, the distance between chucks was 10 mm, the load was 5 kg, and the heating rate was 5 ° C./min. The linear expansion coefficient was calculated from the amount of change in the linear expansion coefficient (TMA%) at 120 to 130 ° C. The lower the linear expansion coefficient, the less the film is deformed by heat and the higher the heat resistance.

7) Expandability After separating the separator from the obtained film, the adhesive layer of the film was adhered to an 8-inch ring frame with a rubber roll. Then, a 2 cm square lattice was written on the surface of the film layer with an oil pen. At this time, the length in the MD direction and the length in the TD direction of the lattice were 12 cm, respectively. Next, as shown in FIG. 4A, the ring frame 44 was fixed to the expander so that the surface of the base layer of the film 40 was in contact with the stage 42 of the expander. As the expansion machine, Hugle Electronics HS-1800 was used. Then, as shown in FIG. 4B, the length 44 in the TD direction and the length in the MD direction of the lattice when the film 40 was expanded by raising the stage 44 of the expander by 65 mm were measured. The obtained measured value was applied to the following formula to obtain the expansion rate and the anisotropy of the expansion rate.
Expansion rate (MD direction, TD direction) (%) = 100 × lattice length after expansion / anisotropy of lattice length expansion rate before expansion = (expansion rate in MD direction−expansion rate in TD direction) absolute value

Therefore, the expansion rate indicates the expansion rate of the expandable adhesive film on the stage. As described above, since the stage is raised by 65 mm for all the films, the film on the stage with a low expansion rate does not greatly expand the film on the stage, and the film outside the stage, that is, the end of the stage and the ring frame. It means that the film in between is expanding. Therefore, the 7) expandability corresponds to the expandability required in the dicing process of a semiconductor or the like that expands the film and picks up a semiconductor chip corresponding to the lattice, in the same manner as the evaluation of 7) expandability described above. The ease of necking of the film at the time of expansion is as follows: the film part in contact with the stage (indicated in the table as “on the film”) and the film part in contact with the stage end (in the table, indicated as the end) Thus, whether or not whitening occurred was observed and evaluated as follows.
○: Necking did not occur and expanded evenly Δ: Partial whitening was observed, but uniformly expanded ×: Necking occurred and expanded unevenly

  The smaller the different orientation, the higher the uniformity of expansion. In particular, when the film of the present invention is used for a dicing film for a semiconductor, the distance between elements becomes uniform and it is preferable to pick up. In addition, when used for a semiconductor dicing film, the pick-up property is greatly hindered when necking on the stage.

8) TEM observation A sample piece of the film of Example 2 having a thickness of 100 μm was prepared. Cross sections obtained by cutting this sample piece in the MD direction parallel to the TD direction and the TD direction parallel to each other at a magnification of 10,000 using a transmission electron microscope (TEM, H-7650 manufactured by Hitachi, Ltd.). Each was observed.
1A is a cross-sectional TEM photograph parallel to the MD direction of the film of Example 2, and FIG. 1B is a cross-sectional TEM photograph parallel to the TD direction of the film.

  As shown in Table 6, it can be seen that the films of Examples 1 to 13 have a large expansion ratio, a low orientation of the expansion ratio, and are less likely to cause necking. Further, even at 120 ° C., which is a general temperature reached when the dicing film is heated by a process such as WLP, the coefficient of linear expansion is small, which indicates that the heat resistance is high. Further, when Examples 2, 4, 6, and 8 were compared with Examples 1, 3, 5, and 7, component (A), component (B), and component (C) were combined with respect to 100 parts by weight of component ( It can be seen that the larger the sum of B) and component (C), the less the necking and the like, and the better the expandability. Moreover, when Example 9, 12, and 13 are seen, when the ratio of a component (C) is large, if the ratio of a component (B) is not increased like Example 9, it will be understood that necking etc. are easy to occur. On the other hand, without using the expandable substrate film of the present invention for the substrate layer, the films of Comparative Examples 1 and 2 having the substrate layer composed only of the component (A) have a problem that necking occurs due to expansion. I understand that. 1A and 1B show that the film of Example 2 has a phase dispersion structure. In addition, the light part (relatively light gray part) of the TEM photograph is a phase substantially composed of 4-methyl-1-pentene (co) polymer (A), and the dark part (relatively dark black part) is It is considered that the phase is substantially composed of the thermoplastic elastomer (B) and the propylene (co) polymer (C).

  Since the film of the present invention is excellent in expandability and heat resistance, it can be widely used as an expandable substrate. In particular, since the film of the present invention can be expanded uniformly in the plane, it is preferably used as a dicing film for semiconductors.

10 Dicing film 12 Base material layer (expandable base film)
14 Adhesive layer 22 Wafer 26 Ring frame 30 Dicing film 32 Base material layer (expandable base material film)
34 Adhesive layer 40 Film 42 Stage 44 Ring frame

Claims (17)

Ri 4-methyl-1-pentene (co) expandable base film der comprising a polymer (A) and the thermoplastic elastomer (B), the content of the (B) is (A) and (B) The melting point TmB2 derived from (B) measured by a differential scanning calorimeter (DSC) is 100 ° C. or less or the melting point TmB2 is substantially equal to 3 to 50 parts by weight with respect to 100 parts by weight in total. A base material layer made of an expandable base material film not observed in
An adhesive layer;
An expandable adhesive film. Ri 4-methyl-1-pentene (co) expandable base film der comprising a polymer (A) and the thermoplastic elastomer (B), the content of the (B) is (A) and (B) Extensibility in which 3 to 50 parts by weight with respect to 100 parts by weight in total, and melting point TmB1 measured by differential scanning calorimeter (DSC) of (B) is 100 ° C. or less or substantially no melting point TmB1 is observed A base material layer comprising a base film ;
An adhesive layer;
An expandable adhesive film. The tensile elastic modulus in 23 degreeC measured according to ASTM-0638 of the said 4-methyl-1- pentene (co) polymer (A) in the said expandable base film is 500-2000 Mpa. Or the expandable adhesive film of 2 . 4. The tensile elastic modulus at 23 ° C. measured in accordance with JIS K7113-1 of the thermoplastic elastomer (B) in the expandable substrate film is 1 to 50 MPa. 5. Expandable adhesive film as described in 1. The expandable adhesive film according to any one of claims 1 to 4, wherein the thermoplastic elastomer (B) in the expandable base film is composed of an olefin-based elastomer and / or a styrene-based elastomer. The expandable adhesive film according to any one of claims 1 to 5, wherein a density of the thermoplastic elastomer (B) in the expandable base film is 850 to 980 kg / m ³ . Said expandable substrate film, per 100 parts by weight of the 4-methyl-1-pentene (co) polymer (A) and the thermoplastic elastomer (B) and propylene (co) polymer (C) The expandable adhesive film according to any one of claims 1 to 6, comprising 0.3 to 40 parts by weight of a propylene (co) polymer (C). Said expandable substrate film, see contains the propylene (co) polymer (C), said expandable base film melting TmC2 derived from said measured by differential scanning calorimetry (DSC) (C) for the The expandable adhesive film according to claim 7, which is in a range of 110 to 175 ° C. A TEM image of a cut surface perpendicular to the main surface of the base material layer made of the expandable base film (distance in the film thickness direction of the imaging range is 15 μm and imaging area is 45 μm ² ), and 4-methyl-1- 9. A phase dispersion structure of a phase substantially composed of a pentene (co) polymer (A) and a phase substantially composed of a thermoplastic elastomer (B) is observed. The expandable adhesive film according to one item. 10. The linear expansion coefficient (1 / K) at 120 ° C. of the expandable substrate film is 1.0 × 10 ^{−4 to} 2.0 × 10 ⁻³ . Expandable adhesive film . The expandable adhesive film according to any one of claims 1 to 10, wherein the adhesive layer has a tensile elastic modulus at 25 ° C of 50 MPa or less. The temperature rising rate of the adhesive layer is 2 ° C./min. The expandable pressure-sensitive adhesive film according to any one of claims 1 to 11, wherein a thermal weight reduction rate when the temperature is raised from room temperature to 200 ° C is less than 2%. Expandable pressure-sensitive adhesive film according to any one of claims 1 to 12 having the adhesive layer on the outermost surface. The expandable adhesive film according to any one of claims 1 to 13 , wherein a tensile elastic modulus at 25 ° C of a layer other than the base material layer is less than a tensile elastic modulus at 25 ° C of the base material layer. The dicing film for semiconductors which comprises the expandable adhesive film as described in any one of Claims 1 thru | or 14 . A step of attaching the dicing film according to claim 15 to a semiconductor wafer via an adhesive layer of the dicing film, a step of dicing the semiconductor wafer to obtain a semiconductor chip, and expanding the dicing film, Picking up the semiconductor chip; and a method of manufacturing a semiconductor device. A step of attaching the dicing film according to claim 15 to a surface of the semiconductor wafer having a circuit surface facing the circuit surface through an adhesive layer of the film; and a step of sealing the circuit surface of the semiconductor wafer; A method for manufacturing a semiconductor device, comprising: a step of dicing the semiconductor wafer to obtain a semiconductor chip; and a step of expanding the dicing film and picking up the semiconductor chip.